Treating peat for manufacturing an insulating material



Patented Sept. 19, 1922.

RUDQLE GRAEFFE, OF BRAND-ERBISDORF, NEAR FREIBERG, GERMANY.

TREATING- IPEAT FOR MANUFACTURING AN INSULATING MATERIAL.

5N0 Drawing.

To all whom it may concern:

I Be it known that I, RUnoLF GRAEFFE, a' subject of Germany, andresiding at Brand- Erbisdorf, near Freiberg, in Saxony, Germany, haveinvented certain new and use- ,ful Improvements in Treating Peat forManufacturing an Insulating Material (Germany, Gr 48 ,717 VI/80 22ndJuly, 1919, Germany, G 49,491 VI/80 Nov. 11th, 1919), of which thefollowing is a specification.

.This present invention relates to an improved treatment of peat formanufactur-' ing-a high-valued insulating material which byv the specialtreatment hereinafter described is much improved with regard to theinsulating materialheretofore known consisting of a mixture of driedpeat with a powdery binding substance which is put into heating drums'or the like after being mixed in order to be melted- This process couldnot however provide a really valu able, insulating material nor couldthis be obtained by mixing wet peat with respective binding substanceson account of the great iabsorbing capacity of the peat, the latteralways tending to regain its original degree of moisture, of*whichithadfbeen deprived by drying or presslng, from the surroundngatmospheric air or the surroundlng -iflmasonry and besides the peathaving a liability to shrink and swell and thereby changing its volume,according to its being wet or dried which is a great disadvantage tocitsuse as insulating material or the like.

the observation that in order to obtain a really; good insulatingmaterial it is necessary to. destroy the absorbing capacity of the peatand the shrinking and swelling'qualities of the same, this beingobtained by the present process in the most perfect manner as follows ePeat in any desired form and state, that is to. say marshy or dried inpieces or re- Y duced to fibres is boiled in water, whereby the marshywater may be used, and a tossing-tub or the like being adapted tothoroughly disintegrate the peat while boiling; After a boiling time ofabout one hour, in which time the peat deposits itself on the bottom ofthe boiler, coal-tar-pitch is put into the boiling peat, saidpitch beingin a state of foam by preheating the same to 200 C., whereby it will beobserved that the coaltar-pitch in this state is adapted to Applicationfiled January 6, 1921. Serial No. 435,567.

thoroughly saturate the fibres of the peat which are completelydissolved by boiling. lVhile the boiler is being filled with the foamingcoal-tar-pitch the tossing-tub must be set atv rest and will be actuatedagain, when all the coal-tar-pitch has been put into the boiler, theboiling process being simultaneously continued, whereby thecoal-tarpitch is homogeneously and thoroughly mixed with the peat-pulp.This is effected by the liquid pitch entering thoroughly into thedissolved fibres of the peat which are enlarged to their utmost volumeby the boiling process, hereby bursting the wet walls of the cells andcovering the fibres, inside and outside with a thin layer of pitch,whereby the foam forms a kind of medium, by which the coal-tar-pitch isintroduced into the peat.

The effect of the process is as follows (1) The perfectly even cover ofthe peatfibres with a thin well-adhering layer of coal-tar-pitch formsafter the solidifying fast but nevertheless elastic cover round eachfibre which prevents the same from either swelling or shrinking.

(2) The destroying effects of the chemicals whichwere contained in thecoal-tar pitch on the slimy, swelled and colloidal substances of thefibres, taking from the same their water-absorbing qualities.

(3) The entrance of the finest parts of.

the coal-tar-pitch into the ends of the fibres,

whereby in the solidifying of the coal-tar pitch such a pressure isexercised upon the cells of said fibres that the same will presentlyburst, their capacity of absorbing water being destroyed'in this way. v

. The finished pulp of peat and coal-tar influence of any desiredpressure, that is to say steam or compressed air, whereby the wateriswithdrawn from the mass.- Now the moulds are put into hand-or-hydraulicpresses and the mass is reduced to about one half or one quarter of itsprevious volpitch may now be treated with respect to ume. As soon asthese moulds hereby obtained are cooled they are ready for use. It ishowever advisable to store the same some short time before using inorder that the same may dry a little more, Whereafter the moulds arestill less liable to breakage and disforming by pressure or the like.The same are perfectly even and show the characteristics as cited above.

It is however possible to form the peat even after being dried in theabove described manner, in wetting the same a little but not more thanto about 25% of its dry weight and only in such a manner that no dustmay rise in working the peat. This wet material is again filled intofast and well closed moulds and is reduced to about one third of itsprevious volume in heatable hand-or-hydraulic presses.

As in pressing the mpulds of the peat-pulp the moulds used thereby areto be heated again to about 100 0, whereby a quick evaporation of thewater which had been added to the peat before filling it into the mouldsis effected, which results in a chemical process very favourable to thepressing action and the peat retaining into once given form so that in avery few minutes a perfectly even and homogeneous body is producedWithin the pressing forms.

In order to obtain moulds ofstill greater firmness the peat may be mixedduring its boiling process with a certain quantity of hot wet pottersclay or else, if the pressed bodies must have a special resistanceagainst heat, kieselguhr must be added besides such potters clay.

Finally the above described material may be used for manufacturingartificial stones for building purposes in adding thereto cement, lime,gypsum or the like.

It must be still observed that according to the above describedinvention a very valuable material is obtained. It may now be possiblethat in certain instances a less valuable and therefore less expensivematerial may be used as well. In this case it is sufficient to ad dtothe peat before boiling. the same a well heated (unto 100 C.) quantityof coal-tar-pitch. By boiling both these ingredients together a goodmixture of the fibres and the pitch may be obtained though the same willbe less even and perfect than the mixture according .to the originalform of the present invention.

A third possibility exists in preparing a still more valuable materialthan in the first-named example by the peat being not, only dessicatedbut roasted at a still higher temperature and changed into coal,whereafter it may be treated as described in the first form of theprocess. Hereby a material is obtained which possesses quite anextraordinary insulating capacity against cold and heat, so that it maybe used in special cases. In further treating this material the mass maybe filled into roasting pans instead of being simply dried after themixing process and roasted therein in respective quantities. Thisrepeated roasting may be prolonged till the formation of coal,Whereafter the roasted mass is filled into heatable presses in order tobe pressed into moulds orlike forms. It is evident that such forming maybe done in the same time with the" brought to foam by. preheating toabout 200 C. being mixed ith said peat during the boiling processWherea'fter the thorough ly mixed material is dried and treated according to its further use that is pressed and formed into" plates,substantially as described. 7

2. The herein described insulating material composed of peat beingboiled in water and coal-tar-pitch having been brought to foam bypreheating the same to about 200 C. being miXedfW-ithsaid peat theretoduring theboiling; process, where-- after the thoroughly mixed materialis pressed in moulds While hot and before being dried, said moulds beingbrought under the influence of steam or air under pressure whereafterthe moulds are pressed inhan'dor-hydra-ulic presses, substantially as described.

8. The herein described insulating Ina-- teri'al composed of peat andcoal-tar-pitcli,

said peat being roasted before its being boiled with the foamingcoal-tar-pitch and the finished material being roasted again to turninto coal during its treatment in the; presses or moulds, substantiallyas described. In testimony whereof I aflix my signature in presence oftwo Witnesses.

RUDOLF GRAEFFE.

lVitnesses Dr. LANDESKROENER, O. REINI'QKE,

